I bought a vial in the spring and ended up pitching it into a historical porter that I had aging in a secondary. I had considered brewing a beer with it as the primary yeast, but the more I researched it, it seemed you really need to have a 16-18% beer if you want the sherry flor to do its thing... and I didn't want that.
The sherry flor didn't do anything in the secondary, so after a few months I ended up dumping a bunch of sour bugs into the beer. Haven't tried the beer since then.
Here is the original thread, with some commentary from a guy who used it as the primary yeast.